public virtual void ApplyStyleSheetSkin(Page page) { // Nothing to do if the control is not in a Page. if (page == null) { return; } // Only apply stylesheet if not already applied. if (flags[styleSheetApplied]) { throw new InvalidOperationException(SR.GetString(SR.StyleSheetAreadyAppliedOnControl)); } if (page.ApplyControlStyleSheet(this)) { flags.Set(styleSheetApplied); } }